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Ahrens S, Laux J, Müller C, Thiel CM. Increased dopamine availability magnifies nicotine effects on cognitive control: A pilot study. J Psychopharmacol 2020; 34:548-556. [PMID: 32133910 PMCID: PMC7370651 DOI: 10.1177/0269881120907989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
INTRODUCTION AND OBJECTIVES The ability to adapt to new task demands flexibly and to stabilise performance in the presence of distractors is termed cognitive control and is mediated by dopaminergic and cholinergic neurotransmission. We aimed to test the hypothesis that the effect of the cholinergic agonist nicotine on cognitive control depends on baseline dopamine levels. METHODS Thirty-eight healthy non-smokers (16 males; Mage=24.05 years) performed a cognitive control task including distractor and switch trials twice. Subjects were split into two parallel groups. One group received 2 g of L-tyrosine two hours prior to testing to manipulate dopamine availability experimentally, while the other group received placebo on both days. One hour later, both groups received in a within-subject design: on one day, a 7 mg nicotine patch; on the other day, a matched placebo. Response time costs for distractor and switch trials served as measures of cognitive stability and flexibility. RESULTS Nicotinic modulation reduced response time costs in switch trials and increased costs in distractor trials (nicotine×condition, p=0.027) with a trend-wise interaction between nicotine, L-tyrosine and trial type (nicotine×L-tyrosine×condition, p=0.068), which was due to stronger nicotine effects under L-tyrosine. CONCLUSIONS Our data provide preliminary evidence that nicotine has opponent effects on cognitive stability and flexibility. Subjects who received the dopamine precursor L-tyrosine were more prone to nicotine effects on behaviours, which are improvements in cognitive flexibility at the cost of decreased cognitive stability.
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Affiliation(s)
- Stefan Ahrens
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany,Stefan Ahrens, Biological Psychology, Department of Psychology, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, Oldenburg, 26111, Germany. Emails: ;
| | - Joana Laux
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Christina Müller
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Christiane M Thiel
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany,Cluster of Excellence ‘Hearing4all’, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany,Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
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Tumilty L, Gregory N, Beckmann M, Thatcher R. No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm Environment. Med Sci Sports Exerc 2019; 52:1404-1413. [PMID: 31834099 DOI: 10.1249/mss.0000000000002245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Tyrosine administration may counter exercise fatigue in a warm environment, but the typical dose is inconclusive, with little known about higher doses. We explored how three tyrosine doses influenced the circulating ratio of tyrosine/amino acids competing for brain uptake and hypothesized that a medium and high dose would enhance exercise performance in a warm environment. METHODS Eight recreationally trained, non-heat-acclimated male individuals (mean ± SD age, 23 ± 4 yr; stature, 181 ± 7 cm; body mass, 76.1 ± 5.9 kg; peak oxygen uptake, 4.1 ± 0.5 L·min) performed a peak oxygen uptake test, two familiarization trials, then four experimental trials in a randomized order separated by 7 d. Before exercise, subjects drank 2 × 300 mL sugar-free drinks delivering 0 (PLA), 150 (LOW), 300 (MED), or 400 (HIGH) mg·kg body mass tyrosine in a double-blind fashion. Subjects performed a 60-min constant intensity cycling then a simulated time trial in 30°C and 60% relative humidity. RESULTS Time trial performance (P = 0.579) was not influenced by tyrosine ingestion. The plasma ratio of tyrosine/∑(free-tryptophan, leucine, isoleucine, valine, phenylalanine, methionine), a key determinant of brain tyrosine influx, increased relative to PLA (P < 0.001). The increase was similar (P > 0.05) in MED (7.7-fold) and HIGH (8.2-fold), and greater than that in LOW (5.3-fold; P < 0.05). No differences existed between trials in core and skin temperature, heart rate, RPE, or thermal sensation (P > 0.05). CONCLUSION Exercise performance in a warm environment was not influenced by tyrosine availability in recreationally trained male individuals. The results provide novel data informing future studies, on the tyrosine dose maximizing the circulating ratio of tyrosine/amino acids competing for brain uptake.
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Affiliation(s)
- Les Tumilty
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Wales, UNITED KINGDOM
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Dopaminergic impact of cART and anti-depressants on HIV neuropathogenesis in older adults. Brain Res 2019; 1723:146398. [PMID: 31442412 DOI: 10.1016/j.brainres.2019.146398] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/09/2019] [Accepted: 08/19/2019] [Indexed: 01/21/2023]
Abstract
The success of combination antiretroviral therapy (cART) has transformed HIV infection into a chronic condition, resulting in an increase in the number of older, cART-treated adults living with HIV. This has increased the incidence of age-related, non-AIDS comorbidities in this population. One of the most common comorbidities is depression, which is also associated with cognitive impairment and a number of neuropathologies. In older people living with HIV, treating these overlapping disorders is complex, often creating pill burden or adverse drug-drug interactions that can exacerbate these neurologic disorders. Depression, NeuroHIV and many of the neuropsychiatric therapeutics used to treat them impact the dopaminergic system, suggesting that dopaminergic dysfunction may be a common factor in the development of these disorders. Further, changes in dopamine can influence the development of inflammation and the regulation of immune function, which are also implicated in the progression of NeuroHIV and depression. Little is known about the optimal clinical management of drug-drug interactions between cART drugs and antidepressants, particularly in regard to dopamine in older people living with HIV. This review will discuss those interactions, first examining the etiology of NeuroHIV and depression in older adults, then discussing the interrelated effects of dopamine and inflammation on these disorders, and finally reviewing the activity and interactions of cART drugs and antidepressants on each of these factors. Developing better strategies to manage these comorbidities is critical to the health of the aging, HIV-infected population, as the older population may be particularly vulnerable to drug-drug interactions affecting dopamine.
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Ethanolamine and Phosphatidylethanolamine: Partners in Health and Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:4829180. [PMID: 28785375 PMCID: PMC5529665 DOI: 10.1155/2017/4829180] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 06/01/2017] [Indexed: 12/18/2022]
Abstract
Phosphatidylethanolamine (PE) is the second most abundant phospholipid in mammalian cells. PE comprises about 15–25% of the total lipid in mammalian cells; it is enriched in the inner leaflet of membranes, and it is especially abundant in the inner mitochondrial membrane. PE has quite remarkable activities: it is a lipid chaperone that assists in the folding of certain membrane proteins, it is required for the activity of several of the respiratory complexes, and it plays a key role in the initiation of autophagy. In this review, we focus on PE's roles in lipid-induced stress in the endoplasmic reticulum (ER), Parkinson's disease (PD), ferroptosis, and cancer.
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Lang JA, Smaller KA. Orall-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adults. Exp Physiol 2017; 102:835-844. [DOI: 10.1113/ep086329] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/03/2017] [Indexed: 11/08/2022]
Affiliation(s)
- James A. Lang
- Department of Physical Therapy; Des Moines University; Des Moines IA 50312 USA
| | - Kevin A. Smaller
- Department of Neuroscience; Drake University; Des Moines IA 50311 USA
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Brodnik ZD, Double M, España RA, Jaskiw GE. L-Tyrosine availability affects basal and stimulated catecholamine indices in prefrontal cortex and striatum of the rat. Neuropharmacology 2017; 123:159-174. [PMID: 28571714 DOI: 10.1016/j.neuropharm.2017.05.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/22/2017] [Accepted: 05/26/2017] [Indexed: 12/15/2022]
Abstract
We previously found that L-tyrosine (L-TYR) but not D-TYR administered by reverse dialysis elevated catecholamine synthesis in vivo in medial prefrontal cortex (MPFC) and striatum of the rat (Brodnik et al., 2012). We now report L-TYR effects on extracellular levels of catecholamines and their metabolites. In MPFC, reverse dialysis of L-TYR elevated in vivo levels of dihydroxyphenylacetic acid (DOPAC) (L-TYR 250-1000 μM), homovanillic acid (HVA) (L-TYR 1000 μM) and 3-methoxy-4-hydroxyphenylglycol (MHPG) (L-TYR 500-1000 μM). In striatum L-TYR 250 μM elevated DOPAC. We also examined L-TYR effects on extracellular dopamine (DA) and norepinephrine (NE) levels during two 30 min pulses (P2 and P1) of K+ (37.5 mM) separated by t = 2.0 h. L-TYR significantly elevated the ratio P2/P1 for DA (L-TYR 125 μM) and NE (L-TYR 125-250 μM) in MPFC but lowered P2/P1 for DA (L-TYR 250 μM) in striatum. Finally, we measured DA levels in brain slices using ex-vivo voltammetry. Perfusion with L-TYR (12.5-50 μM) dose-dependently elevated stimulated DA levels in striatum. In all the above studies, D-TYR had no effect. We conclude that acute increases within the physiological range of L-TYR levels can increase catecholamine metabolism and efflux in MPFC and striatum. Chronically, such repeated increases in L-TYR availability could induce adaptive changes in catecholamine transmission while amplifying the metabolic cost of catecholamine synthesis and degradation. This has implications for neuropsychiatric conditions in which neurotoxicity and/or disordered L-TYR transport have been implicated.
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Affiliation(s)
- Zachary D Brodnik
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States
| | - Manda Double
- Medical Research Service, Louis Stokes Cleveland DVAMC, 10701 East Blvd., Cleveland, OH 44106, United States
| | - Rodrigo A España
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States
| | - George E Jaskiw
- Medical Research Service, Louis Stokes Cleveland DVAMC, 10701 East Blvd., Cleveland, OH 44106, United States; Dept. of Psychiatry, Case Western University Medical Center at W.O. Walker 10524 Euclid Ave, Cleveland, OH 44133, United States.
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Teodorak BP, Scaini G, Carvalho-Silva M, Gomes LM, Teixeira LJ, Rebelo J, De Prá SDT, Zeni N, Schuck PF, Ferreira GC, Streck EL. Antioxidants reverse the changes in energy metabolism of rat brain after chronic administration of L.-tyrosine. Metab Brain Dis 2017; 32:557-564. [PMID: 27924409 DOI: 10.1007/s11011-016-9936-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/29/2016] [Indexed: 12/17/2022]
Abstract
Tyrosinemia type II is a rare autosomal recessive disease caused by deficiency of hepatic tyrosine aminotransferase and is associated with neurologic and development difficulties in numerous patients. Considering that the mechanisms underlying the neurological dysfunction in hypertyrosinemic patients are poorly known and that high concentrations of tyrosine provoke mitochondrial dysfunction and oxidative stress, in the present study we investigated the in vivo influence of antioxidants (N-acetylcysteine, NAC; and deferoxamine, DFX) administration on the inhibitory effects on parameters of energy metabolism in cerebral cortex, hippocampus and striatum of rats, provoked by chronic administration of L.-tyrosine. Our results showed that chronic administration of L.-tyrosine results in a marked decrease in the activity of citrate synthase in all the analyzed structures and succinate dehydrogenase activities in hippocampus and striatum, and that antioxidants administration can prevent this inhibition in hippocampus and striatum. Moreover, chronic administration of L.-tyrosine inhibited the activity of complex I, II-III and IV in the striatum, which can be prevented by antioxidant treatment. However, the co-administration of NAC plus DFX could not prevent the inhibition of creatine kinase activity in the striatum. In conclusion, the present study demonstrates that the administration of antioxidants NAC and DFX attenuates the L.-tyrosine effects on enzymes of the Krebs cycle and the mitochondrial respiratory chain, suggesting that impairment of energy metabolism can be involved with oxidative stress. These results also indicate a possible neuroprotective role for NAC and DFX as a potential adjuvant therapy to the patients with Tyrosinemia type II.
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Affiliation(s)
- Brena P Teodorak
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Giselli Scaini
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Milena Carvalho-Silva
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Lara M Gomes
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Letícia J Teixeira
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Joyce Rebelo
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Samira D T De Prá
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Neila Zeni
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil
| | - Patrícia F Schuck
- Laboratório de Erros Inatos do Metabolismo, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil
| | - Gustavo C Ferreira
- Laboratório de Neuroquímica, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Emilio L Streck
- Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105, Criciúma, SC, 88806-000, Brazil.
- Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Porto Alegre, RS, Brazil.
- Núcleo de Excelência em Neurociências Aplicadas de Santa Catarina (NENASC), Florianópolis, Santa Catarina, Brazil.
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Lieberman HR, Thompson LA, Caruso CM, Niro PJ, Mahoney CR, McClung JP, Caron GR. The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stress. Psychopharmacology (Berl) 2015; 232:943-51. [PMID: 25220844 PMCID: PMC4325185 DOI: 10.1007/s00213-014-3727-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 08/22/2014] [Indexed: 12/01/2022]
Abstract
RATIONALE Acute stress produces behavioral and physiological changes modulated by central catecholamines (CA). Stress increases CA activity, and depletion of CA stores reduces responses to stress. Increasing CA activity by administration of the dietary amino acid CA precursor tyrosine may increase responsiveness to stress. This study determined whether tyrosine enhances the ability of humans to respond to severe stress. METHODS Severe psychological stress was generated during training at Survival, Evasion, Resistance, and Escape (SERE) School. The acute stressor consisted of two mock interrogations conducted during several days of simulated captivity. Seventy-eight healthy male and female military personnel participated in this double-blind, between-subjects study, in which they received either tyrosine (300 mg/kg, N = 36) or placebo (N = 36). Tyrosine (or placebo) was administered in food bars in two doses of 150 mg/kg each approximately 60 min before each mock interrogation. Mood (Profile of Mood States), saliva cortisol, and heart rate (HR) were assessed prior to stress exposure during a week of academic training preceding mock captivity and immediately following the mock interrogations. RESULTS The severe stress produced robust effects on mood (i.e., increased tension, depression, anger, fatigue, vigor, and confusion; p < .001), cortisol, and HR (p < .001). Tyrosine increased anger (p = .002, ANOVA treatment condition by test session interaction) during stress but had no other effects. CONCLUSION Tyrosine did not alter most subjective or physiological responses to severe acute stress, but it increased ratings of anger. The modest increase in anger may be an adaptive emotional response in stressful environments.
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Affiliation(s)
- Harris R. Lieberman
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760 USA
| | - Lauren A. Thompson
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760 USA
| | - Christina M. Caruso
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760 USA
| | - Philip J. Niro
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760 USA
| | - Caroline R. Mahoney
- Cognitive Sciences, US Army Natick Soldier Research, Development, and Engineering Center, Kansas Street, Natick, MA 01760 USA
| | - James P. McClung
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760 USA
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Matveychuk D, Nunes E, Ullah N, Aldawsari FS, Velázquez-Martínez CA, Baker GB. Elevation of rat brain tyrosine levels by phenelzine is mediated by its active metabolite β-phenylethylidenehydrazine. Prog Neuropsychopharmacol Biol Psychiatry 2014; 53:67-73. [PMID: 24607770 DOI: 10.1016/j.pnpbp.2014.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 11/26/2022]
Abstract
Phenelzine, a non-selective irreversible inhibitor of monoamine oxidase (MAO), has been used in the treatment of depression and anxiety disorders for several decades. It is a unique inhibitor of MAO as it is also a substrate for MAO, with one of the metabolites being β-phenylethylidenehydrazine (PEH), and it also inhibits several transaminases (e.g. GABA transaminase) in the brain when administered i.p. to rats. Administration of either phenelzine or PEH to rats has been reported to produce dramatic increases in rat brain levels of GABA and alanine while reducing levels of glutamine; these effects are abolished for phenelzine, but not for PEH, when the animals are pre-treated with another MAO inhibitor, suggesting that they are mediated by the MAO-catalyzed formation of PEH from phenelzine. In the present report, we have found that phenelzine and E- and Z-geometric isomers of PEH significantly increased rat whole brain concentrations of L-tyrosine. In a time-response study, acute administration of phenelzine, E-PEH and Z-PEH (30 mg/kg i.p.) elevated rat whole brain L-tyrosine levels at 3 and 6h following injection, reaching approximately 265-305% of vehicle-treated controls at 3h. To determine whether the effect on L-tyrosine is MAO-dependent, animals were pre-treated with the non-selective MAO inhibitor tranylcypromine (1mg/kg i.p.) prior to administration of phenelzine, racemic PEH or vehicle controls. This pre-treatment reversed the effects of phenelzine, but not of PEH, on brain L-tyrosine levels, suggesting that the tyrosine-elevating property of phenelzine is largely the result of its active metabolite PEH. These results are discussed in relation to possible therapeutic applications of these drugs.
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Affiliation(s)
- Dmitriy Matveychuk
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Canada.
| | - Emerson Nunes
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Canada.
| | - Nasir Ullah
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
| | - Fahad S Aldawsari
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
| | | | - Glen B Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Canada; Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
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TUMILTY LES, DAVISON GLEN, BECKMANN MANFRED, THATCHER RHYS. Failure of Oral Tyrosine Supplementation to Improve Exercise Performance in the Heat. Med Sci Sports Exerc 2014; 46:1417-25. [DOI: 10.1249/mss.0000000000000243] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Choi S, DiSilvio B, Fernstrom MH, Fernstrom JD. Effect of chronic protein ingestion on tyrosine and tryptophan levels and catecholamine and serotonin synthesis in rat brain. Nutr Neurosci 2012; 14:260-7. [PMID: 22053757 DOI: 10.1179/1476830511y.0000000019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Previous studies have shown that brain tyrosine (TYR) levels and catecholamine synthesis rate increase in rats as chronic dietary protein content increases from 2 to 10% (% weight). A single protein, casein, was examined. The present study explores how TYR levels and catecholamine synthesis (and tryptophan (TRP) levels and serotonin synthesis) change when different proteins are ingested chronically over the same range of dietary protein contents. METHODS Male rats ingested for 8 days diets contain 2 or 10% protein (zein, gluten, casein, soy protein, or alpha-lactalbumin). On the last day, they were killed 2.5 hours into the dark period, 30 minutes after receiving an injection of m-hydroxybenzylhydrazine, an inhibitor of aromatic l-amino acid decarboxylase. Brain samples were analyzed for amino acids, including 5-hydroxytryptophan (index of serotonin synthesis rate) and dihydroxyphenylalanine (index of catecholamine synthesis rate), by HPLC-electrochemical detection. RESULTS TYR levels and catecholamine synthesis rate in brain were unaffected by the particular protein ingested. However, TRP levels and serotonin synthesis rate varied markedly, depending on the protein ingested, with effects being most prominent in the 10% protein groups. The effect of dietary protein on brain TRP correlated very highly with its effect on serotonin synthesis. DISCUSSION The results indicate that the protein ingested can chronically modify TRP levels and serotonin synthesis in brain, but not TYR levels or catecholamine synthesis, with effects most distinct at an adequate level of protein intake (10%).
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Affiliation(s)
- SuJean Choi
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI 53201, USA
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Nguyen MAT, Joya JE, Kee AJ, Domazetovska A, Yang N, Hook JW, Lemckert FA, Kettle E, Valova VA, Robinson PJ, North KN, Gunning PW, Mitchell CA, Hardeman EC. Hypertrophy and dietary tyrosine ameliorate the phenotypes of a mouse model of severe nemaline myopathy. ACTA ACUST UNITED AC 2011; 134:3516-29. [PMID: 22067542 DOI: 10.1093/brain/awr274] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Nemaline myopathy, the most common congenital myopathy, is caused by mutations in genes encoding thin filament and thin filament-associated proteins in skeletal muscles. Severely affected patients fail to survive beyond the first year of life due to severe muscle weakness. There are no specific therapies to combat this muscle weakness. We have generated the first knock-in mouse model for severe nemaline myopathy by replacing a normal allele of the α-skeletal actin gene with a mutated form (H40Y), which causes severe nemaline myopathy in humans. The Acta1(H40Y) mouse has severe muscle weakness manifested as shortened lifespan, significant forearm and isolated muscle weakness and decreased mobility. Muscle pathologies present in the human patients (e.g. nemaline rods, fibre atrophy and increase in slow fibres) were detected in the Acta1(H40Y) mouse, indicating that it is an excellent model for severe nemaline myopathy. Mating of the Acta1(H40Y) mouse with hypertrophic four and a half LIM domains protein 1 and insulin-like growth factor-1 transgenic mice models increased forearm strength and mobility, and decreased nemaline pathologies. Dietary L-tyrosine supplements also alleviated the mobility deficit and decreased the chronic repair and nemaline rod pathologies. These results suggest that L-tyrosine may be an effective treatment for muscle weakness and immobility in nemaline myopathy.
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Affiliation(s)
- Mai-Anh T Nguyen
- Neuromuscular and Regenerative Medicine Unit, School of Medical Sciences, University of New South Wales, Kensington, NSW 2052, Australia
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Wurtman RJ, Cansev M, Sakamoto T, Ulus I. Nutritional modifiers of aging brain function: use of uridine and other phosphatide precursors to increase formation of brain synapses. Nutr Rev 2010; 68 Suppl 2:S88-101. [PMID: 21091953 DOI: 10.1111/j.1753-4887.2010.00344.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Brain phosphatide synthesis requires three circulating compounds: docosahexaenoic acid (DHA), uridine, and choline. Oral administration of these phosphatide precursors to experimental animals increases the levels of phosphatides and synaptic proteins in the brain and per brain cell as well as the numbers of dendritic spines on hippocampal neurons. Arachidonic acid fails to reproduce these effects of DHA. If similar increases occur in human brain, administration of these compounds to patients with diseases that cause loss of brain synapses, such as Alzheimer's disease, could be beneficial.
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Affiliation(s)
- Richard J Wurtman
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Wurtman RJ, Cansev M, Sakamoto T, Ulus IH. Use of phosphatide precursors to promote synaptogenesis. Annu Rev Nutr 2009; 29:59-87. [PMID: 19400698 DOI: 10.1146/annurev-nutr-080508-141059] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
New brain synapses form when a postsynaptic structure, the dendritic spine, interacts with a presynaptic terminal. Brain synapses and dendritic spines, membrane-rich structures, are depleted in Alzheimer's disease, as are some circulating compounds needed for synthesizing phosphatides, the major constituents of synaptic membranes. Animals given three of these compounds, all nutrients-uridine, the omega-3 polyunsaturated fatty acid docosahexaenoic acid, and choline-develop increased levels of brain phosphatides and of proteins that are concentrated within synaptic membranes (e.g., PSD-95, synapsin-1), improved cognition, and enhanced neurotransmitter release. The nutrients work by increasing the substrate-saturation of low-affinity enzymes that synthesize the phosphatides. Moreover, uridine and its nucleotide metabolites activate brain P2Y receptors, which control neuronal differentiation and synaptic protein synthesis. A preparation containing these compounds is being tested for treating Alzheimer's disease.
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Affiliation(s)
- Richard J Wurtman
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Jaskiw GE, Newbould E, Bongiovanni R. Tyrosine availability modulates potassium-induced striatal catecholamine efflux in vivo. Brain Res 2008; 1209:74-84. [DOI: 10.1016/j.brainres.2008.02.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/14/2008] [Accepted: 02/15/2008] [Indexed: 11/17/2022]
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17
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Kaur H, Arora SP. Dietary Effects on Ruminant Livestock Reproduction with Particular Reference to Protein. Nutr Res Rev 2007; 8:121-36. [DOI: 10.1079/nrr19950009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Fernstrom JD, Fernstrom MH. Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain. J Nutr 2007; 137:1539S-1547S; discussion 1548S. [PMID: 17513421 DOI: 10.1093/jn/137.6.1539s] [Citation(s) in RCA: 394] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Aromatic amino acids in the brain function as precursors for the monoamine neurotransmitters serotonin (substrate tryptophan) and the catecholamines [dopamine, norepinephrine, epinephrine; substrate tyrosine (Tyr)]. Unlike almost all other neurotransmitter biosynthetic pathways, the rates of synthesis of serotonin and catecholamines in the brain are sensitive to local substrate concentrations, particularly in the ranges normally found in vivo. As a consequence, physiologic factors that influence brain pools of these amino acids, notably diet, influence their rates of conversion to neurotransmitter products, with functional consequences. This review focuses on Tyr and phenylalanine (Phe). Elevating brain Tyr concentrations stimulates catecholamine production, an effect exclusive to actively firing neurons. Increasing the amount of protein ingested, acutely (single meal) or chronically (intake over several days), raises brain Tyr concentrations and stimulates catecholamine synthesis. Phe, like Tyr, is a substrate for Tyr hydroxylase, the enzyme catalyzing the rate-limiting step in catecholamine synthesis. Tyr is the preferred substrate; consequently, unless Tyr concentrations are abnormally low, variations in Phe concentration do not affect catecholamine synthesis. Unlike Tyr, Phe does not demonstrate substrate inhibition. Hence, high concentrations of Phe do not inhibit catecholamine synthesis and probably are not responsible for the low production of catecholamines in subjects with phenylketonuria. Whereas neuronal catecholamine release varies directly with Tyr-induced changes in catecholamine synthesis, and brain functions linked pharmacologically to catecholamine neurons are predictably altered, the physiologic functions that utilize the link between Tyr supply and catecholamine synthesis/release are presently unknown. An attractive candidate is the passive monitoring of protein intake to influence protein-seeking behavior.
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Affiliation(s)
- John D Fernstrom
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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Venero JL, Herrera AJ, Machado A, Cano J. Changes in neurotransmitter levels associated with the deficiency of some essential amino acids in the diet. Br J Nutr 2007; 68:409-20. [PMID: 1359904 DOI: 10.1079/bjn19920098] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The contents of dopamine (DA) and serotonin (5-HT) and their metabolites were measured in rat substantia nigra and corpus striatum following dietary changes, including restriction of protein content (low-protein diet; LPD) and the contents of several large neutral amino acids (isoleucine, leucine, methionine, phenylalanine, tryptophan and valine) for 25 d. The LPD produced an increase in the concentration of tyrosine (TYR) in the two regions of the brain studied. This effect was also observed with all amino acid deficiencies studied except for valine in the substantia nigra, tryptophan in the striatum and phenylalanine in both regions. Likewise, the concentration of 5-hydroxyindolacetic acid (5-HIAA), the main metabolite of 5-HT, increased in the substantia nigra but not in the striatum after LPD, as well as with all the amino acid deficiencies studied, with the exception of tryptophan deficiency. In this case there was a dramatic effect on all components of the serotoninergic system, with decreases in the concentration of tryptophan (TRP; precursor), 5-HT and 5-HIAA. This behaviour clearly shows an interrelationship between precursor (TRP) availability and 5-HT synthesis and metabolism. With valine deficiency, dopaminergic and serotoninergic systems demonstrated opposite effects in the substantia nigra and the corpus striatum, and the behaviour of the two monoamines was also opposite within each structure. The significance of these changes is discussed.
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Affiliation(s)
- J L Venero
- Departamento de Bioquímica, Bromatología y Toxicología, Universidad de Sevilla, Spain
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Jaskiw GE, Kirkbride B, Bongiovanni R. In rats chronically treated with clozapine, tyrosine depletion attenuates the clozapine-induced in vivo increase in prefrontal cortex dopamine and norepinephrine levels. Psychopharmacology (Berl) 2006; 185:416-22. [PMID: 16541248 DOI: 10.1007/s00213-005-0283-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Accepted: 11/28/2005] [Indexed: 11/28/2022]
Abstract
We previously reported that depletion of brain tyrosine attenuated the acute clozapine (CLZ)-induced increase in medial prefrontal cortex (MPFC) dopamine (DA) levels. This effect was now examined after chronic CLZ treatment. Male rats received CLZ (10 mg kg(-1) day(-1)) in drinking water for 21 days. On day 18, a cannula was stereotaxically implanted over the MPFC. A microdialysis probe was inserted on day 20. On day 21 after a stable baseline was reached, rats received an acute injection of vehicle (VEH) or a tyrosine- and phenylalanine-free mixture of neutral amino acid [NAA(-)] (total 1 g kg(-1), i.p., two injections, 1 h apart) followed by CLZ (10 mg kg(-1), i.p.) or VEH. Basal tyrosine or norepinephrine (NE) levels were not different between the groups, but basal DA was higher in the group treated chronically with CLZ (p<0.05). Acute CLZ (10 mg kg(-1), i.p.) increased MPFC DA and NE levels to 370% and 510% of baseline, respectively, and similarly in rats chronically pretreated with CLZ or VEH. NAA(-) did not affect basal MPFC DA or NE levels but significantly attenuated acute CLZ-induced DA (220% of baseline) and NE (330% of baseline) levels (p<0.01) in rats pretreated chronically with CLZ or with VEH. These data demonstrate that even after chronic CLZ administration, the acute CLZ-induced increases in MPFC DA and NE levels depend on the availability of brain tyrosine. Judicious manipulation of brain tyrosine levels may provide a useful probe as well as a mechanism for enhancing psychotropic drug actions.
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Affiliation(s)
- George E Jaskiw
- Louis Stokes Department of Veterans Affairs Medical Center, Cleveland, OH, USA.
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Breier JM, Bankson MG, Yamamoto BK. L-tyrosine contributes to (+)-3,4-methylenedioxymethamphetamine-induced serotonin depletions. J Neurosci 2006; 26:290-9. [PMID: 16399699 PMCID: PMC6674330 DOI: 10.1523/jneurosci.3353-05.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The specific mechanisms underlying (+)-3,4-methylenedioxymethamphetamine (MDMA)-induced damage to 5-HT terminals are unknown. Despite the hypothesized role for dopamine (DA) and DA-derived free radicals in mediating this damage, it remains unclear why MDMA produces long-term depletions of 5-HT in brain regions that are sparsely innervated by DA neurons. We hypothesized that the precursor to DA biosynthesis, tyrosine, mediates MDMA-induced 5-HT depletions. Extracellular tyrosine concentrations increased fivefold in striatum and 2.5-fold in hippocampus during the administration of neurotoxic doses of MDMA. In vitro results show that L-tyrosine can be hydroxylated nonenzymatically to the DA precursor l-3,4-dihydroxyphenylalanine (DOPA) under pro-oxidant conditions. The local infusion of L-tyrosine into the striatum or hippocampus during MDMA administration potentiated the acute increase in extracellular DA and the long-term depletion of 5-HT after MDMA. Coinfusion of the aromatic amino acid decarboxylase (AADC) inhibitor m-hydroxybenzylhydrazine attenuated these effects in hippocampus and decreased basal extracellular DA in the striatum. In contrast, the reverse dialysis of the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine into the hippocampus did not affect MDMA-induced increases in extracellular DA or the long-term depletion in 5-HT. These results show that MDMA increases the concentration of tyrosine in the brain to cause a long-term depletion of 5-HT via the nonenzymatic, tyrosine hydroxylase-independent, hydroxylation of tyrosine to DOPA and subsequently to DA via AADC. Overall, the findings suggest that MDMA depletes 5-HT by increasing tyrosine and its eventual conversion to DA within 5-HT terminals.
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Affiliation(s)
- Joseph M Breier
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Jaskiw GE, Kirkbride B, Newbould E, Young D, Durkalski V, Bongiovanni R. Clozapine-induced dopamine release in the medial prefrontal cortex is augmented by a moderate concentration of locally administered tyrosine but attenuated by high tyrosine concentrations or by tyrosine depletion. Psychopharmacology (Berl) 2005; 179:713-24. [PMID: 15682305 DOI: 10.1007/s00213-004-2091-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Accepted: 10/18/2004] [Indexed: 11/28/2022]
Abstract
RATIONALE Tyrosine availability can affect indices of dopamine (DA) release in activated central DA systems. There are, however, inconsistencies between studies. One possibility is that the relationship between tyrosine availability and DA release is non-linear. OBJECTIVES This study aimed to determine how tyrosine depletion as well as a range of administered tyrosine concentrations affect antipsychotic drug-induced extracellular DA levels in the MPFC or striatum. METHODS A guide cannula was implanted over the medial prefrontal cortex or striatum of adult male rats. After a 24-h recovery period, a microdialysis probe was inserted. Microdialysate collection began on the following day. Some rats received vehicle or a tyrosine- and phenylalanine-free neutral amino acid solution NAA(-) (IP) prior to clozapine (CLZ 10 mg/kg IP). Others received vehicle, CLZ (10 mg/kg IP) or haloperidol (HAL) (1 mg/kg IP) while the probe was perfused with artificial cerebrospinal fluid containing tyrosine 0-200 mug/ml. RESULTS NAA(-) reduced tyrosine levels in MPFC dialysate by 35%. This reduction did not affect basal MPFC DA levels but attenuated the peak of CLZ-induced MPFC DA levels. The NAA(-) effect could be reversed by administration of tyrosine. Infused tyrosine 12.5-200 mug/ml did not affect basal DA levels either in MPFC or striatum. Within the MPFC, tyrosine 50.0 mug/ml significantly increased CLZ-induced DA levels. Within the striatum, tyrosine 25.0 mug/ml significantly increased while 150.0 mug/ml significantly decreased HAL-induced DA levels. CONCLUSIONS Basal extracellular levels of DA in the MPFC and striatum are not affected by wide changes in tyrosine availability. However, modestly increased brain tyrosine levels can augment CLZ-induced MPFC and HAL-induced DA levels. Very high tyrosine concentrations attenuate HAL-induced striatal DA levels. These data may explain inconsistencies in the literature and suggest that tyrosine availability could be exploited to modulate psychotropic drug-induced DA levels in the brain.
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Affiliation(s)
- George E Jaskiw
- Psychiatry Service, Louis Stokes Cleveland Veterans Administration Medical Center, Cleveland, Ohio, USA.
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Lieberman HR, Georgelis JH, Maher TJ, Yeghiayan SK. Tyrosine prevents effects of hyperthermia on behavior and increases norepinephrine. Physiol Behav 2004; 84:33-8. [PMID: 15642604 DOI: 10.1016/j.physbeh.2004.10.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Accepted: 10/13/2004] [Indexed: 11/19/2022]
Abstract
Tyrosine (TYR) is the precursor of the catecholamine (CA) neurotransmitters, dopamine (DA) and norepinephrine (NE). Catecholamines, especially NE, participate in the response of the brain to acute stress. When animals are acutely stressed, NE neurons become more active and tyrosine availability may be rate-limiting. Tyrosine administration, before exposure to physical and/or environmental stressors including cold, reduces the adverse behavioral, physiological and neurochemical consequences of the exposure. In this study, the effects of tyrosine (400 mg/kg) were examined on rats exposed to heat stress, for which its effects have not been examined. Coping behavior and memory were assessed using the Porsolt swim test and the Morris water maze. Release of hippocampal NE and DA was assessed with in vivo microdialysis. In vehicle-treated animals, heat impaired coping and memory, and increased release of NE, but not DA. In heated animals receiving tyrosine, coping was not impaired and NE release was sustained, thus demonstrating tyrosine protects against the adverse effects of heat, and suggesting these effects result from increased central NE release. This study indicates the effects of tyrosine generalize across dissimilar stressors and that tyrosine administration may mitigate the adverse behavioral effects of heat and other stressors on humans. In addition, it demonstrates that moderate heat stress impairs coping behavior, as well as working and reference memory.
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Affiliation(s)
- Harris R Lieberman
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Building 42, Kansas Street, Natick, MA 01760-5007, USA.
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Chinevere TD, Sawyer RD, Creer AR, Conlee RK, Parcell AC. Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performance. J Appl Physiol (1985) 2002; 93:1590-7. [PMID: 12381742 DOI: 10.1152/japplphysiol.00625.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test the effects of tyrosine ingestion with or without carbohydrate supplementation on endurance performance, nine competitive cyclists cycled at 70% peak oxygen uptake for 90 min under four different feeding conditions followed immediately by a time trial. At 30-min intervals, beginning 60 min before exercise, each subject consumed either 5 ml/kg body wt of water sweetened with aspartame [placebo (Pla)], polydextrose (70 g/l) (CHO), L-tyrosine (25 mg/kg body wt) (Tyr), or polydextrose (70 g/l) and L-tyrosine (25 mg/kg body wt) (CHO+Tyr). The experimental trials were given in random order and were carried out by using a counterbalanced double-blind design. No differences were found between treatments for oxygen uptake, heart rate, or rating of perceived exertion at any time during the 90-min ride. Plasma tyrosine rose significantly from 60 min before exercise to test termination (TT) in Tyr (means +/- SE) (480 +/- 26 micromol) and CHO+Tyr (463 +/- 34 micromol) and was significantly higher in these groups from 30 min before exercise to TT vs. CHO (90 +/- 3 micromol) and Pla (111 +/- 7 micromol) (P < 0.05). Plasma free tryptophan was higher after 90 min of exercise, 15 min into the endurance time trial, and at TT in Tyr (10.1 +/- 0.9, 10.4 +/- 0.8, and 12.0 +/- 0.9 micromol, respectively) and Pla (9.7 +/- 0.5, 10.0 +/- 0.3, and 11.7 +/- 0.5 micromol, respectively) vs. CHO (7.8 +/- 0.5, 8.6 +/- 0.5, and 9.3 +/- 0.6 micromol, respectively) and CHO+Tyr (7.8 +/- 0.5, 8.5 +/- 0.5, 9.4 +/- 0.5 micromol, respectively) (P < 0.05). The plasma tyrosine-to-free tryptophan ratio was significantly higher in Tyr and CHO+Tyr vs. CHO and Pla from 30 min before exercise to TT (P < 0.05). CHO (27.1 +/- 0.9 min) and CHO+Tyr (26.1 +/- 1.1 min) treatments resulted in a reduced time to complete the endurance time trial compared with Pla (34.4 +/- 2.9 min) and Tyr (32.6 +/- 3.0 min) (P < 0.05). These findings demonstrate that tyrosine ingestion did not enhance performance during a cycling time trial after 90 min of steady-state exercise.
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Affiliation(s)
- Troy D Chinevere
- Human Performance Research Center, Brigham Young University, Provo, Utah 84602, USA
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Hamdi A, Brock JW, Payne S, Ross KD, Bond SP, Prasad C. Dietary Tyrosine Protects Striatal Dopamine Receptors from the Adverse Effects of REM Sleep Deprivation. Nutr Neurosci 1998; 1:119-31. [PMID: 27406017 DOI: 10.1080/1028415x.1998.11747221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
L-Tyrosine is a non-essential amino acid that is produced as an intermediary metabolite in the conversion of phenylalanine to 3,4-dihyroxyphenylalanine (DOPA), and is a precursor of the neurotransmitter dopamine. In previous studies, tyrosine pretreatment was shown to protect against the neurochemical and behavioral deficits of acute stress caused by tail shock or cold exposure in rodents. The present study addressed the hypothesis that tyrosine administration may be an effective counter-measure to dopamine-mediated behaviors induced by rapid eye-movement sleep deprivation (RSD). In order to test the hypothesis, Sprague-Dawley rats were divided into 9 treatment groups: RSD-treated rats on normal-protein diet (20% casein: 1% tyrosine, 1% valine); tank control (TC) rats on a normal diet; cage control (CC) rats on normal diet; RSD-treated rats on 4% tyrosine diet; TC rats on 4% tyrosine diet; CC rats on 4% tyrosine diet; RSD-treated rats on 4% valine diet; TC rats on 4% valine diet; CC rats on 4% valine diet. In the RSD group receiving tyrosine, there was no apparent change in Bmax for binding of the dopamine D2 receptor ligand [(3)H]YM-09151-2 in the striata as compared to the respective TC and CC groups; whereas RSD-treated rats maintained on the normal diet and valine supplementation demonstrated expected increases in Bmax for ligand binding. The TC group on the tyrosine diet showed attenuated catalepsy compared to the corresponding CC group, while the RSD group consuming tyrosine showed a catalepsy that was significantly increased, and similar to that of cage control animais on a control diet. These data suggest that the tyrosine-supplemented diet significantly attenuated RSD-induced changes in striatal dopamine D2 receptors, and the effect appeared sufficient to influence RSD-induced behaviors.
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Affiliation(s)
- A Hamdi
- a Department of Pharmacology , King Saud University College of Medicine , Abha , Saudi Arabia
| | - J W Brock
- b Neurobehavioral Research Institute , Nashville , Tennessee 37211 , USA
| | - S Payne
- b Neurobehavioral Research Institute , Nashville , Tennessee 37211 , USA
| | - K D Ross
- b Neurobehavioral Research Institute , Nashville , Tennessee 37211 , USA
| | - S P Bond
- b Neurobehavioral Research Institute , Nashville , Tennessee 37211 , USA
| | - C Prasad
- c Section of Endocrinology, Department of Medicine , Louisiana State University Medical Center , New Orleans , Louisiana 70112 , USA
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Okura Y, Tanaka R, Ono K, Yoshida S, Tanuma N, Matsumoto Y. Treatment of rat hemiparkinson model with xenogeneic neural transplantation: Tolerance induction by anti-T-cell antibodies. J Neurosci Res 1997. [DOI: 10.1002/(sici)1097-4547(19970601)48:5<385::aid-jnr1>3.0.co;2-a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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During MJ, Leone P. Targets for gene therapy of Parkinson's disease: growth factors, signal transduction, and promoters. Exp Neurol 1997; 144:74-81. [PMID: 9126155 DOI: 10.1006/exnr.1996.6391] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Parkinson's disease gene therapy is in its infancy. All studies to date have been in experimental animals and there are no clinical protocols currently approved. Several non-human primate studies however, have been completed and preliminary data appear promising. When dealing with a complex acquired disorder of unknown etiology, gene therapy is likely to provide symptomatic and palliative relief at best and will not be curative. However, if the gene therapy approach has advantages in terms of the risk/benefit ratio, cost and efficacy over current treatments, then it should be brought to clinical trial. This article discusses some future directions and areas of intense investigation at present. The advances in the field over the past five years have been tremendous and it appears possible that before the year 2000, clinical gene therapy trials in Parkinson's disease will be ongoing.
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Affiliation(s)
- M J During
- Department of Neurosurgery, Yale Univeristy School of Medcine, New Haven, Connecticut 06520, USA
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Schwarting RK, Huston JP. Unilateral 6-hydroxydopamine lesions of meso-striatal dopamine neurons and their physiological sequelae. Prog Neurobiol 1996; 49:215-66. [PMID: 8878304 DOI: 10.1016/s0301-0082(96)00015-9] [Citation(s) in RCA: 255] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
One of the primary approaches in experimental brain research is to investigate the effects of specific destruction of its parts. Here, several neurotoxins are available which can be used to eliminate neurons of a certain neurochemical type or family. With respect to the study of dopamine neurons in the brain, especially within the basal ganglia, the neurotoxin 6-hydroxydopamine (6-OHDA) provides an important tool. The most common version of lesion induced with this toxin is the unilateral lesion placed in the area of mesencephalic dopamine somata or their ascending fibers, which leads to a lateralized loss of striatal dopamine. This approach has contributed to neuroscientific knowledge at the basic and clinical levels, since it has been used to clarify the neuroanatomy, neurochemistry, and electrophysiology of mesencephalic dopamine neurons and their relationships with the basal ganglia. Furthermore, unilateral 6-OHDA lesions have been used to investigate the role of these dopamine neurons with respect to behavior, and to examine the brain's capacity to recover from or compensate for specific neurochemical depletions. Finally, in clinically-oriented research, the lesion has been used to model aspects of Parkinson's disease, a human neurodegenerative disease which is neuronally characterized by a severe loss of the meso-striatal dopamine neurons. In the present review, which is the first of two, the lesion's effects on physiological parameters are being dealt with, including histological manifestations, effects on dopaminergic measures, other neurotransmitters (e.g. GABA, acetylcholine, glutamate), neuromodulators (e.g. neuropeptides, neurotrophins), electrophysiological activity, and measures of energy consumption. The findings are being discussed especially in relation to time after lesion and in relation to lesion severeness, that is, the differential role of total versus partial depletions of dopamine and the possible mechanisms of compensation. Finally, the advantages and possible drawbacks of such a lateralized lesion model are discussed.
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Affiliation(s)
- R K Schwarting
- Institute of Physiological Psychology I, Heinrich-Heine University of Düsseldorf, Germany
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Gariepy KC, Bailey B, Yu J, Maher T, Acworth IN. Simultaneous Determination of Norepinephrine, Dopamine, and Serotonin in Hippocampal Microdialysis Samples Using Normal Bore High Performance Liquid Chromatography: Effects of Dopamine Receptor Agonist Stimulation and Euthanasia. ACTA ACUST UNITED AC 1994. [DOI: 10.1080/10826079408013177] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Farooqui SM, Brock JW, Onaivi ES, Hamdi A, Prasad C. Differential modulation of dopaminergic systems in the rat brain by dietary protein. Neurochem Res 1994; 19:167-76. [PMID: 8183426 DOI: 10.1007/bf00966812] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rats that consume a diet 50% rich in protein exhibit hyperactivity and hyperresponsiveness to nociceptive stimuli, in which facilitation of dopaminergic activity has been implicated. We studied the regional changes in the concentrations of dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the brains of rats that were maintained on high-protein (HP, 50% casein), normal-protein (NP, 20% casein), and low-protein (LP, 8% casein) diets for 36 weeks. Brain nuclei that represented different DAergic systems were punch-dissected and analyzed using HPLC. In the substantia nigra, the striatum, and the dentate gyrus, DA concentrations decreased and increased, respectively, with a decrease and increase in dietary protein (p < 0.05 compared to the NP diet). Similar trends in the effect of the HP diet were observed in the ventral tegmental area, amygdala, frontal cortex, subiculum, centromedial nucleus (CM) of the thalamus, and inferior colliculi (IC), although the differences in DA concentrations were not statistically significant. These brain areas also showed a pattern of decreased DA concentration in association with the LP diet, and the differences were statistically significant (p < 0.05) in the CM and IC. DA concentrations in most regions of the midbrain and brainstem were not different between the diet groups, nor were consistent trends observed in those regions. Also, there were no consistent relationships between DOPAC/DA and HVA/DA ratios and dietary protein level. These data suggest that only discrete dopaminergic neuronal circuits in the rat forebrain were sensitive to changes in dietary protein level.
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Affiliation(s)
- S M Farooqui
- Laboratory of Neurosciences, Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808
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Abstract
In vivo microdialysis was used to examine the effect of two new catechol-O-methyltransferase (COMT) inhibitors, Ro 40-7592 and OR-611, on extracellular levels of dopamine, dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in rat striatum. The interactions of the COMT inhibitors with nomifensine, clorgyline and deprenyl were also studied. Ro 40-7592 (3-30 mg/kg, i.p.) decreased dose-dependently the efflux of HVA, increased that of DOPAC, and tended to increase that of dopamine. Higher doses of OR-611 (30-100 mg/kg, i.p.) also decreased the dialysate level of HVA, increased that of DOPAC, and tended to increase that of dopamine. Ro 40-7592 was about ten-fold as potent as OR-611. Neither of the COMT inhibitors changed dialysate levels of 5-HIAA. An OR-611 dose of 10 mg/kg i.p. had no significant effect, in contrast to Ro 40-7592, on any of the parameters studied; this dose was thus used to differentiate between the effects of central and peripheral COMT inhibition. Both nomifensine (15 mg/kg, i.p.) and clorgyline (4 mg/kg, i.p.) alone elevated extracellular dopamine levels, and lowered those of DOPAC and HVA, though there were quantitative and temporal differences between the drugs. L-Deprenyl (1 mg/kg, i.p.) alone had no significant effect on any of the compounds measured. Ro 40-7592 (10 mg/kg, i.p.) potentiated the effect of nomifensine on dopamine efflux, and it tended to increase clorgyline-induced dopamine efflux.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Kaakkola
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139
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33
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Sharp T, Bramwell SR, Grahame-Smith DG. Effect of acute administration of L-tryptophan on the release of 5-HT in rat hippocampus in relation to serotoninergic neuronal activity: an in vivo microdialysis study. Life Sci 1992; 50:1215-23. [PMID: 1569829 DOI: 10.1016/0024-3205(92)90321-f] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Here we have used the brain microdialysis method to test the effect of the 5-HT precursor L-tryptophan on 5-HT release. The release of endogenous 5-HT was measured in ventral hippocampus of the anesthetized rat both under basal conditions and when serotoninergic neuronal activity was raised by electrical stimulation of the dorsal raphe nucleus (DRN). Low frequency electrical stimulation of the DRN evoked a frequency-dependent (2-10 Hz) release of hippocampal 5-HT. The electrically evoked release of 5-HT was markedly enhanced by pretreatment with L-tryptophan (50 and 100 mg/kg i.p.). The effect of L-tryptophan on evoked release of 5-HT was dose-related, detectable at low (2 Hz) stimulation frequencies, and became stronger as the stimulation frequency increased. L-Tryptophan (10, 50 and 100 mg/kg i.p.) had no effect on basal output of 5-HT. We conclude from these findings that elevation of 5-HT precursor availability increases 5-HT release in hippocampus in vivo under conditions of increased serotoninergic neuronal activity.
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Affiliation(s)
- T Sharp
- M.R.C. Unit of Clinical Pharmacology, Radcliffe Infirmary, Oxford, U.K
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34
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Dubach M. Distribution of intracerebrally injected dopamine as studied by a punch-scintillation modeling technique. Neuroscience 1991; 45:103-15. [PMID: 1754060 DOI: 10.1016/0306-4522(91)90107-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Three-dimensional distribution gradients of intracerebrally injected tritiated dopamine were calculated on the basis of concentrations in multiple punch-samples from sequential sections of Macaca fascicularis brain tissue. The monkey was pretreated systemically with a monoamine oxidase inhibitor to retard elimination. Gradients were best fit by cubic exponential equations relating concentration to distance from the center of the site. The concentration at the center, total amount of label, and total extent of the site injected just before perfusion were consistent with initial distribution in the extracellular space, if the volume fraction of the latter is estimated at 20%. The extent of distribution was distinctly greater in the mediolateral and dorsoventral dimensions than in the anteroposterior dimension. The total amount of label near the site decreased rapidly in the first few minutes after injection, then much more slowly, reaching about 30% of the injected amount after 2 h. Its distribution within the site changed steadily, the outer boundary gradually expanding and the peak at the center gradually decreasing. This pattern was consistent with an initial rapid dispersion by injection pressure and an initial loss of tritiated dopamine due to disruption of the blood-brain barrier at the center of the site, followed by a steady expansion of the site driven by diffusion and bulk flow.
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Affiliation(s)
- M Dubach
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle 98195
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35
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Westerink BH, De Vries JB. Effect of precursor loading on the synthesis rate and release of dopamine and serotonin in the striatum: a microdialysis study in conscious rats. J Neurochem 1991; 56:228-33. [PMID: 1898966 DOI: 10.1111/j.1471-4159.1991.tb02585.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of systemic administration of tyrosine and phenylalanine on the extracellular levels of tyrosine and dopamine were determined by microdialysis in the striatum of awake rats. In addition, the effects of these precursors on in vivo 3,4-dihydroxyphenylalanine (DOPA) formation were determined during continuous infusion of a decarboxylase inhibitor. Both precursors increased the dialysate levels of tyrosine sixfold, but only phenylalanine administration stimulated DOPA formation. However, neither precursor affected the release of dopamine. When the precursor administration was repeated in rats in which the release of dopamine was stimulated by haloperidol pretreatment, again no effect was seen on the release of dopamine. Systemic administration of tryptophan (100 mg/kg, i.p.) during continuous infusion of a decarboxylase inhibitor induced a threefold increase in the formation of 5-hydroxytryptophan and caused an increase in the release of serotonin during infusion of an uptake inhibitor to about 150% of controls. Finally, we investigated whether dietary precursors were able to influence neurotransmitter formation and release. Rats trained to consume their daily food in a period of 2 h were implanted with microdialysis probes. Scheduled eating induced a small increase in the extracellular levels of tyrosine (135% of controls), but the release of dopamine and the formation of 5-hydroxytryptophan during continuous infusion of a decarboxylase inhibitor were not affected.
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Affiliation(s)
- B H Westerink
- Department of Medicinal Chemistry, University Centre for Pharmacy, Groningen, The Netherlands
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Kreutz MR, Acworth IN, Lehnert H, Wurtman RJ. Systemic administration of thyrotropin-releasing hormone enhances striatal dopamine release in vivo. Brain Res 1990; 536:347-52. [PMID: 1707722 DOI: 10.1016/0006-8993(90)90049-h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We examined the effects of systemically administered thyrotropin-releasing hormone (TRH) on the release of dopamine (DA), as assessed by brain microdialysis within the corpus striatum of anesthetized rats. A single dose (10 micrograms i.v.) elevated DA levels in brain extracellular fluid (ECF) by 240% above baseline levels after 150 min. Systemic tyrosine ([TME] 20 mg/kg i.v.) also increased DA release (by 190% after 150 min), while combined treatment with both agents was associated with significant potentiation of the DA response (to 640% after 150 min). None of the treatments significantly altered striatal tissue levels of DA or its metabolites. A large dose of TRH (50 micrograms i.v.) significantly increased DA release (by 1150%) whether or not animals had received an active or denatured prolactin (PRL) antiserum prior to the experiment, suggesting that the TRH effect is not mediated by PRL. Although TRH is rapidly metabolized in plasma and penetrates the blood-brain barrier only poorly, our results suggest that even relatively small doses of the hormone can affect striatal dopaminergic neurotransmission.
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Affiliation(s)
- M R Kreutz
- Department of Molecular Neuroendocrinology, Max-Planck-Institute for Experimental Medicine, Göttingen, F.R.G
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